A novel approach to the generation of antibodies against G protein-coupled (GPCR) receptors using NMR and synthetic peptide mimics is proposed. Such a method has enormous potential in research and medical sciences. Antibodies to GPCRs are powerful tools that make possible the development of assays useful in drug discovery. Antibodies find uses in the investigation of GPCRs by numerous methods including diagnostics or therapeutics (function-blocking antibodies). Preliminary results using Edg1 as a model demonstrate the utility of NMR in identifying the ligand binding domain, residues and conformation of the extracellular loops of GPCR's. Molecular modeling studies will be applied to determine the optimal design of the solvent exposed loops of the endothelial Edg6 GPCR. NMR will be used to characterize interactions between the extracellular loops and O-phosphoethanolamine, a mimic of the Edg6 endogenous ligand. These data will be used to design a peptide mimic of the binding site. The designed peptides will be structurally characterized by NMR to verify a stable tertiary structure with conformations consistent with the molecular model for overlapping regions.GPCR's are a superfamily of membrane-spanning proteins having seven alpha-helical transmembrane domains that are involved in the transduction of signals across cellular membranes. About 1-2 percent of human genes code for GPCR, and up to 60 percent of pharmacopoeia target them. The Edg family consist sof B phospholipid growth factor receptors. Edg receptors participate in angiogenesis, cell proliferation/cellular motility. Edg receptors are difficult to study due to their wide distribution and overlapping expression of more than one subtype of Edg receptor in most cells.